Re: [RFC][PATCH 5/5] firmware: QCOM_SCM: Allow qcom_scm driver to be loadable as a permenent module

From: Marc Zyngier
Date: Tue Jun 16 2020 - 03:55:09 EST


Hi John,

+Will for the SMMU part.

On 2020-06-16 07:13, John Stultz wrote:
Allow the qcom_scm driver to be loadable as a
permenent module.

Cc: Andy Gross <agross@xxxxxxxxxx>
Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx>
Cc: Saravana Kannan <saravanak@xxxxxxxxxx>
Cc: Todd Kjos <tkjos@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: linux-arm-msm@xxxxxxxxxxxxxxx
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: linux-gpio@xxxxxxxxxxxxxxx
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
drivers/firmware/Kconfig | 2 +-
drivers/firmware/Makefile | 3 ++-
drivers/firmware/qcom_scm.c | 4 ++++
drivers/iommu/Kconfig | 2 ++
4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index fbd785dd0513..9e533a462bf4 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -236,7 +236,7 @@ config INTEL_STRATIX10_RSU
Say Y here if you want Intel RSU support.

config QCOM_SCM
- bool
+ tristate "Qcom SCM driver"
depends on ARM || ARM64
select RESET_CONTROLLER

diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 99510be9f5ed..cf24d674216b 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -17,7 +17,8 @@ obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o
-obj-$(CONFIG_QCOM_SCM) += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
+obj-$(CONFIG_QCOM_SCM) += qcom-scm.o
+qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o
obj-$(CONFIG_TRUSTED_FOUNDATIONS) += trusted_foundations.o
obj-$(CONFIG_TURRIS_MOX_RWTM) += turris-mox-rwtm.o
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 0e7233a20f34..b5e88bf66975 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -1155,6 +1155,7 @@ static const struct of_device_id qcom_scm_dt_match[] = {
{ .compatible = "qcom,scm" },
{}
};
+MODULE_DEVICE_TABLE(of, qcom_scm_dt_match);

static struct platform_driver qcom_scm_driver = {
.driver = {
@@ -1170,3 +1171,6 @@ static int __init qcom_scm_init(void)
return platform_driver_register(&qcom_scm_driver);
}
subsys_initcall(qcom_scm_init);
+
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. SCM driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index b510f67dfa49..714893535dd2 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -381,6 +381,7 @@ config SPAPR_TCE_IOMMU
config ARM_SMMU
tristate "ARM Ltd. System MMU (SMMU) Support"
depends on (ARM64 || ARM || (COMPILE_TEST && !GENERIC_ATOMIC64)) && MMU
+ depends on QCOM_SCM || !QCOM_SCM #if QCOM_SCM=m this can't be =y

This looks a bit ugly. Could you explain why we need this at the SMMU level? I'd have expected the dependency to flow the other way around...

select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
select ARM_DMA_USE_IOMMU if ARM
@@ -500,6 +501,7 @@ config QCOM_IOMMU
# Note: iommu drivers cannot (yet?) be built as modules
bool "Qualcomm IOMMU Support"
depends on ARCH_QCOM || (COMPILE_TEST && !GENERIC_ATOMIC64)
+ depends on QCOM_SCM=y
select IOMMU_API
select IOMMU_IO_PGTABLE_LPAE
select ARM_DMA_USE_IOMMU

Thanks,

M.
--
Jazz is not dead. It just smells funny...